This invention relates to an apparatus and method for placing particular articles in a particular manner, and specifically to changing the attitude of an article relative to the direction that article is conveyed. In particular, this invention relates to moving workpieces from a conveyor system to a system for processing the workpieces by using at least one sensor to indicate when a workpiece may be moved from the conveyor system to the processing system.
Apparatus and methods for conveying workpieces to a system for processing these workpieces have existed for many years. Two industries that utilize these kinds of apparatus and methods are the lumber industry and the steel industry. A typical conveyance arrangement utilizes chains or belts to move lumber or metal pieces along in a side-by-side manner so that they can be processed one at a time. A problem that arises with these apparatus is how to move one workpiece at a time from the conveyor system to a processing system. Another problem that arises is how to prevent a workpiece that is being moved from interfering with the proper handling of another workpiece, particularly the immediately previous or subsequent workpiece. For example, a workpiece cannot be moved too early or it may land on top of or interfere in another manner with a previous workpiece.
A conventional way to solve these problems spaces workpieces apart on a conveyor system so that their timely conveyance to a processing system prevents these problems. That is, each workpiece is sufficiently spaced apart from adjacent workpieces so that it does not interfere with moving or handling the adjacent workpieces. Jackson, U.S. Pat. No. 5,992,484, Method and Apparatus for Positioning Flitches or Cants for a Board Edger or Gang Saw, describes such a solution for moving boards on a conveyor system. A rotational framework is synchronized with the conveyor using a timing chain or belt, so that a platform can rotate under a board to lift the board from the conveyor and onto a bed of rollers. To use this solution, the conveyor system needs a mechanism such as sequencing duckers to keep the boards properly spaced. Moreover, the width of the boards that can be lifted and the spacing of the sequencing duckers on which the boards must be placed are directly affected by the size of the rotational framework.
An alternative solution incorporates sensing devices into conveyor systems to assist in handling workpieces. Ritola, U.S. Pat. No. 5,685,410, Infeed Conveyor System, for example, describes scanning devices used to determine desired cutting patterns for a saw and the length, width, and profile of a board. Walker, Jr., U.S. Pat. No. 5,208,962, Method and Apparatus for Affixing Tags on Lumber, describes sensors used to staple tags to boards, and Weislogel et al., U.S. Pat. No. 4,606,387, Machine and Method for Trimming a Stack of Veneers, describes sensors used to control trimming veneer sheets. In Raybon et al., U.S. Pat. No. 5,605,216, Board Turning Apparatus, photocells are used to both scan boards to determine board quality as well as to detect the leading edge of a board that needs to be flipped over. Kohlberg, U.S. Pat. No. 3,970,128, Orientation of Cant for Translatory Feed Through Edging Cutters, also uses sensors to find the leading edge of a board. Neither of these latter two inventions, however, resolves how to distinguish between abutting workpieces on a conveyor system. Consequently, spacing workpieces is still used to move workpieces along in a side-by-side manner so that they can be processed one at a time.
While existing conveyor system schemes have addressed many of the efficiency problems of moving workpieces from a conveyor system to a processing system, it would be advantageous to have a system capable of sensing or otherwise distinguishing the front edge of one workpiece from the back edge of the previous workpiece as they move side-by-side. In doing so, devices to space workpieces become unnecesary, more footage can be loaded onto a conveyor system at anytime, and workpieces of greater width can be moved.
Preferred embodiments of the present invention relate to an intelligent deck apparatus and method. The intelligent deck apparatus is used for serially moving workpieces positioned side-by-side on a conveyor system to a processing system. By deploying a workpiece edge detector system, the intelligent deck eliminates having to space workpieces when they are loaded onto a conveyor system or use any special mechanisms with the conveyor system to ensure that workpieces timely arrive at the other end of the conveyor system. Workpieces need only travel in their typical manner, transversely to their longitudinal dimension, so that each workpiece can be distinguished by a sensor. Thus, multiple workpieces can be loaded onto a conveyor system and more footage can be loaded onto a conveyor system at any one time. The intelligent deck also can accommodate workpieces having greater widths and workpieces of varying widths. Finally, as those skilled in the art are aware, a variety of means for loading workpieces onto a live deck of a conveyor system, whether manual or electromechanical such as magazine unloaders, can be used with the intelligent deck. The intelligent deck uses simple parts, so it is also easy to operate and maintain. Thus, human intervention is minimal, and workers can attend more to stocking workpieces and/or operating other machines.
The intelligent deck is used on the receiving end of a conveyor system. A manual or automatic loading system can be used to load workpieces onto the conveyor system so that they travel in a side-by-side manner transversely to their longitudinal dimension towards the receiving end of the conveyor system. A preferred embodiment of an intelligent deck is comprised of a computer system, an edge detector system, and a shift mechanism. The computer system is used for processing signals from the edge detector system and sending well timed signals to the conveyor system and the shift mechanism. The computer system is also operatively connected to the processing system. The edge detector system includes at least one sensor, although a plurality of sensors could be used. The edge detector system is operatively connected to the computer system and is positioned and arranged on the receiving end of the conveyor system for detecting the next edge of the leading workpiece that is in line with the at least one sensor. The phrase xe2x80x9cin line with the at least one sensorxe2x80x9d means that the respective workpiece is positioned such that it will trigger or actuate the at least one sensor if the workpiece continues moving in the direction that the converyor system has been moving it. The phrase xe2x80x9cleading workpiecexe2x80x9d refers to the workpiece that is both closest to the receiving end of the conveyor system and satisfies any specified conditions; and the phrase xe2x80x9cnext edgexe2x80x9d refers to the next edge that is to pass over, under, or through, whichever is appropriate, the at least one sensor. The edge detector system signals the computer system, which then activates the shift mechanism at the appropriate times. The shift mechanism is also operatively connected to the computer system and positioned and arranged on the receiving end of the conveyor system. The shift mechanism is used for shifting a workpiece so that the at least one sensor can subsequently detect the next edge of the leading workpiece that is in line with the at least one sensor. Preferably the shift mechanism will move the leading workpiece longitudinally.
A preferred embodiment may further consist of a lift arm system. The conveyor system is used to move a workpiece into a position so that the lift arm system can receive and move the workpiece from the conveyor system to a processing system. The lift arm system is operatively connected to the computer system to receive signals therefrom and has at least one lift arm and a means to actuate the lift arm. To ensure that a workpiece will be moved to a processing system only in a manner that does not interfere with previous workpieces, a preferred embodiment also can include a workpiece processing detection system. The workpiece processing detection system is operatively connected to the computer system to send signals thereto and is positioned and arranged so that it detects when previous workpieces have progressed sufficiently so that they will not be affected by moving another workpiece to a processing system. As those skilled in the art are aware, one or a combination of several kinds of sensors can be used as the means of detection, such as photo, optic, magnetic, or pressure sensitive sensing devices. The workpiece processing detection system also may be used to stop and start the conveyor system, control its speed, or coordinate the movements of workpieces in any similar manner.